I believe that simple, unicellular creatures exist in the outer space, but I don't think that aliens exist as we imagine them - and if they do, they look completely different from how we imagine them.
I don't believe in aliens in any of the forms that humans have conceptualized, but I definitely believe there must be intelligent life (or at least some sort of life) out there in the entire freaking endless universe.
I prefer not to use the term 'aliens', but I believe that there is a form of 'life'. Our galaxy is too huge for it not to happen. Now imagine the possibility of life in other galaxies of the universe. It has to exist.
Yes, but I think it will be at least a few hundred years before technology is advanced enough to find them. I think space is so harsh and the "goldilocks zone" is so rare to keep us away from each other. With the mess humans have done to each other, there's no telling what we'll do to extraterrestrials.
I believe we are not alone. I think there's millions of species out there other than humans. I also believe in pararel universes and the theory of a multiverse.